Tray sealer

ABSTRACT

The invention relates to a tray sealer comprising conveyor belts that can be displaced in a direction transversely to the conveying direction.

CROSS-REFERENCE TO RELATED APPLICATION

This Application claims priority to German Application Number 102011106826.4 filed Jul. 7, 2011 to Wolfgang Negele entitled “Tray Sealer,” currently pending, the entire disclosure of which is incorporated herein by reference.

FIELD OF INVENTION

The invention relates generally to a tray sealer.

BACKGROUND

Tray sealers of the type offered also by the applicant are disclosed in DE 10 2008 030 510 A1. In order to achieve high performance, belt speeds and belt accelerations can be varied by the operator making use of the machine control. In regards to high belt speeds and belt accelerations, it is of decisive importance that the bottom of the tray filled with a product adheres to the belt surface of the conveyor. The adherence may also change during the production process due to an increase in air humidity or due to liquid product residues, and this leads to malpositioning on the collecting belt. A gripper system may then perhaps no longer be able to seize the trays and the tray sealer will come to a standstill so that the malfunction can be remedied. These downtimes impair the performance of the tray sealer.

SUMMARY OF THE INVENTION

It is the object of the present invention to resolve this problem with means having the simplest possible structural design.

The tray sealer according to the present invention comprises a conveyor including a supply conveyor and/or a collecting conveyor disposed downstream of the supply conveyor in a conveying direction so as to convey trays to a work station, preferably a sealing station of the tray sealer. The tray sealer is characterized in that the supply conveyor and/or the collecting conveyor each comprise at least two conveyor belts, at least two of these conveyor belts being displaceable in a direction transversely to the conveying direction. The conveyor belts may have the same width, which is more than 50% smaller than the width of a single conveyor belt that has been used for this purpose. Due to the smaller contact surface of narrow conveyor belts, less product residues (e.g., pickle or sauces and dressings that may spill over the edge of the trays) will remain on the conveyor belts. The narrow conveyor belts are faster and easier to clean. The conveyor belts can be adjusted such that product residues running down laterally on the outer surfaces of the trays will not even reach the conveyor belts. This improves the friction of the trays on the conveyor belts thus allowing higher belt speeds and belt accelerations. Process reliability is increased as well. The displaceability of the conveyor belts in a direction transversely to the conveying direction guarantees an optimum adaptation to different tray bottoms and improved contact with maximum adherence.

The conveyor belts are preferably adapted to be driven in a form-fit manner (e.g., by means of toothed belt wheels, chain wheels or drive rolls) so as to be insensitive especially to liquids which, in the case of friction drives, have a negative influence on friction.

In one embodiment, conveyor belts are toothed belts. The toothed side of the toothed belt improves the discharge or displacement of foreign matter on the toothed belts, similar to the tread pattern of a tire.

The toothed belts may have teeth on either side thereof (i.e., on the contact side and on the opposite, inner side) so that the mode of arrangement of the drive will be more flexible.

The toothed belts can advantageously be driven by means of the teeth. The resultant form fit allows different belt tensions and is resistant to contamination and foreign matter.

A special tooth shape of the toothed belt is a round shape without any horizontal support, this kind of shape preventing product residues from depositing.

According to one embodiment, the conveyor belts each have a width of 40 mm or less, preferably 20 mm or less, so as to provide a wide adjustment range and minimize the area where product residues may deposit.

In order to optimize the transfer of the tray from the supply conveyor to the collecting conveyor, at least one conveyor belt of the supply conveyor and at least one conveyor belt of the collecting conveyor have, in the conveying direction, a common and/or neighboring conveying path in the area where the trays are transferred from the supply conveyor to the collecting conveyor.

The conveyor belts can be displaced manually, pneumatically or by an electric motor so as to allow the operator to carry out a fast and easy displacement and so as to permit by means of a control unit of the tray sealer an automatic displacement including storage of the displacement positions in the control unit.

According to one embodiment of the invention, the respective conveyor belts of the supply conveyor and of the collecting conveyor have a common drive shaft, said drive shafts driving the respective conveyor belts. This has the advantage that only one drive motor is provided for a plurality of conveyor belts of a conveyor and that this is a simple and cost-efficient structural design.

Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description.

DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

In the accompanying drawing, which forms a part of the specification and is to be read in conjunction therewith in which like reference numerals are used to indicate like or similar parts in the various views:

FIG. 1 is a side perspective view of a tray sealer in accordance with one embodiment of the present invention;

FIG. 2 is a top perspective view of a supply conveyor comprising two conveyor belts sealer in accordance with one embodiment of the present invention;

FIG. 3 is a top view and a side view of a supply conveyor and of a collecting conveyor according to the prior art;

FIG. 4 a is a top view of a supply conveyor and collecting conveyor variant in accordance with one embodiment of the present invention;

FIG. 4 b is a top view of another supply conveyor and collecting conveyor variant according to the present invention.

Identical components are designated by identical reference numerals throughout the figures. A

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. For purposes of clarity in illustrating the characteristics of the present invention, proportional relationships of the elements have not necessarily been maintained in the drawing figures.

The following detailed description of the invention references specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the present invention. The present invention is defined by the appended claims and the description is, therefore, not to be taken in a limiting sense and shall not limit the scope of equivalents to which such claims are entitled.

FIG. 1 shows in a perspective view a tray sealer 1 according to one embodiment of the present invention. A support frame 2 has provided thereon a work station 3, in the present case as shown, a gas flushing, sealing and cutting station. A supply conveyor 4 and a downstream collecting conveyor 5 convey filled trays (not shown) to the work station 3. A gripper with gripper arms 6 may seize the trays and conveys them into the work station 3. A cover film 8 is unwound from a film dispenser 7 and also conveyed into the work station 3. When the trays have been evacuated and/or gas flushed with a substitute gas (Modified Atmosphere Packaging, MAP), they are hermetically sealed with the cover film 8 unwound from the film dispenser 7. Subsequently, a cutting tool cuts the packaging trays 23 (cf., FIG. 3) out of the cover film 8, i.e. it separates the packages from one another. The residual film grid of the cover film 8 may be wound onto a residual film winder 9. The closed and singulated packages may be placed onto a discharge belt 10 and removed from the work station 3 and from the tray sealer 1 by means of said belt. A display device 11 and control elements 12 can be implemented to visualize the sequence of operating steps and the operating condition of the tray sealer 1 and allow an operator to operate the tray sealer 1.

FIG. 2 shows the supply conveyor 4 comprising two parallel conveyor belts 13 in the form of toothed belts having teeth on one side thereof The conveyor belts 13 are driven in common via a drive roll 14, which is driven by a servo drive 15 and a gear mechanism 16. The teeth 17 of the conveyor belt 13 are directed upwards and outwards, respectively, and are used as a support for the bottom of the tray. By means of deflection pulleys 18 the conveyor belt 13 is guided along the drive roll 14 such that the support-side teeth 17 interact in a form-fit manner with the teeth of the drive roll 14. In one embodiment, both conveyor belts 13 are adjustable on the shafts 19 in a direction transverse to a conveying direction R. By means of releasable clamping rings 20 each conveyor belt 13 can be displaced separately by hand through the operator. When a conveyor belt 13 is being displaced, also the teeth 17 of the conveyor belt 13 will move along the drive roll 14, without any necessity of displacing the drive roll 14. In order to allow slackening of the conveyor belts 13, the belts can be released by means of a locking device 21 so that adjustment, exchange or cleaning of the conveyor belts 13 can be carried out. Each conveyor belt 13 has a width B, which may, for example, in one embodiment may be in a range from about 10 mm to 50 mm, and in another embodiment in a range of about 20 mm to about 40 mm and in yet another embodiment is about 30 mm.

FIG. 3 shows a top view (below) and a side view (above) of a supply conveyor 4 and a subsequent collecting conveyor 5 according to the prior art, each of said conveyors comprising a broad, continuous belt 22. The trays 23 are received on the belt 22 such that the entire surface of the respective tray bottom 24 rests thereon. When the tray 23 is being transferred from the supply conveyor 4 to the collecting conveyor 5, both belts 22 move at the same speed.

FIG. 4 a shows a top view of a supply conveyor 4 and of a collecting conveyor 5 of a tray sealer 1 according one embodiment of the present invention. For allowing a comparison with FIG. 3, the belts 22 are represented in the drawing by a broken line. The conveyor belt 13 of the supply conveyor 4 and the conveyor belt 13 b of the collecting conveyor 5 are adapted to be displaced in a direction transversely to the conveying direction R. One or more stoppers 25 can be provided between the conveyor belts 13, said stoppers 25 being moved from a downward position upwards via the conveying plane, which is defined by the tray bottoms, so that, if necessary, the trays 23 can be stopped on the supply conveyor 4 with the conveyor belt 13 running

Another embodiment is shown in FIG. 4 b. The supply conveyor 4 comprises three conveyor belts 13 and the collecting conveyor 5 comprises two conveyor belts 13 b. The conveyor belts 13 of the supply conveyor 4 project here into the area of the conveyor belts 13 b of the collecting conveyor 5, so that, when the trays 23 are being transferred, the tray bottom 24 will be in full-area contact with the conveyor belt 13 and/or the conveyor belt 13 b. Thus, a common and/or overlapping conveyor path is formed. Making use of the stoppers 25, the trays 23 can be stopped on the collecting conveyor 5 at the fetching position for the gripper arms 6. The speeds of the conveyor belts 13 and 13 b may also be different during transfer of the trays.

It is also imaginable to configure the discharge belt 10 such that it comprises at least two conveyor belts 13, 13 b which are adapted to be displaced in a direction transversely to the conveying direction R. In addition, a double-track tray sealer 1 with laterally displaceable conveyor belts 13, 13 b is imaginable. In particular if an uneven number of conveyor belts is provided, at least one of these belts, e.g. the central one, may be configured as a fixed conveyor belt that cannot be displaced in a direction transversely to the conveying direction.

From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure. It will be understood that certain features and sub combinations are of utility and may be employed without reference to other features and sub combinations. This is contemplated by and is within the scope of the claims. Since many possible embodiments of the invention may be made without departing from the scope thereof, it is also to be understood that all matters herein set forth or shown in the accompanying drawings are to be interpreted as illustrative and not limiting.

The constructions and methods described above and illustrated in the drawings are presented by way of example only and are not intended to limit the concepts and principles of the present invention. Thus, there has been shown and described several embodiments of a novel invention. As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. The terms “having” and “including” and similar terms as used in the foregoing specification are used in the sense of “optional” or “may include” and not as “required”. Many changes, modifications, variations and other uses and applications of the present construction will, however, become apparent to those skilled in the art after considering the specification and the accompanying drawings. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow. 

1. A tray sealer comprising: a conveyor for conveying trays to a work station of the tray sealer in a conveying direction, said conveyor comprising at least two conveyor belts; wherein at least one of said conveyer belts being displaceable in a direction transverse to the conveying direction.
 2. The tray sealer of claim 1, wherein said conveyor includes a supply conveyor and a collecting conveyor disposed downstream of the supply conveyor, said supply conveyor and said collecting conveyor each including at least two said conveyor belts at least one of which is displaceable in a direction transverse to the conveying direction.
 3. The tray sealer of claim 1, wherein all the conveyor belts are adapted to be displaced in a direction transverse to the conveying direction.
 4. The tray sealer of claim 1, wherein the conveyor belts are adapted to be driven in a form-fit manner.
 5. The tray sealer of claim 1, wherein the conveyor belts are toothed belts used for conveying the trays.
 6. The tray sealer of claim 5, wherein the toothed belts have teeth on either side thereof
 7. The tray sealer of claim 6, wherein the toothed belts are adapted to be driven via the teeth.
 8. The tray sealer of claim 6, wherein the teeth of the toothed belts are round in shape.
 9. The tray sealer of claim 1, wherein the conveyor belts each have a width of 40 mm or less.
 10. The tray sealer of claim 1, wherein the conveyor belts each have a width of 20 mm or less.
 11. The tray sealer of claim 2, wherein at least one conveyor belt of the supply conveyor and at least one conveyor belt of the collecting conveyor have, in the conveying direction, a common conveying path in the area where the trays are transferred from the supply conveyor to the collecting conveyor.
 12. The tray sealer of claim 1, wherein the conveyor belts can be displaced manually, pneumatically or by an electric motor.
 13. The tray sealer of claim 2, wherein the respective conveyor belts of the supply conveyor and of the collecting conveyor have a common drive shaft for driving the respective conveyor belts. 